[mercury-users] ambiguous overloading causes type ambiguity.

[Robert Bossy]

> [localhost:mercury/primality/divisors] metaperl% mmc -E --infer-all divisors.m
> divisors.m:010: In clause for predicate `divisors:main/2':
> divisors.m:010:   error: ambiguous overloading causes type ambiguity.
> divisors.m:010:   Possible type assignments include:
> divisors.m:010: V_15 :: string or (pred string)

Sorry, this is entirely my fault, I should have tested the code I posted before. It is because of

>         { W0 = error(Err) },
>         print(io__error_message(Err)), nl
                ^^^^^^^^^^^^^^^^^^^^^^

The compiler can't tell if the highlighted term is the result of function io__error_message/1 (would have type string) or a curried form of io__error_message/2 (would have higher order type pred(string)).

Unambiguated code:

	{ W0 = error(Err),
	  io__error_message(Err,Msg) },
	print(Msg), nl


-- 
sig(Robert,Bossy) :-
      bossy at ccr.jussieu.fr
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